The present invention relates generally to encoder strip having dimensional stability and ink resistance properties for use in a high resolution laser, ink-jet printer, plotter, and in wide-format printers or plotters.
U.S. Pat. No. 5,941,649, entitled, Method For Fabricating A Registration Guide For A Wide-Format Printer Or Plotter, relates to a method for fabricating an encoder containing the intended integer number of registration markings (and spaces) per unit distance, over the correct length of that entire encoder. The method is practiced by producing a template having the desired number of registration indices at reasonably exact tolerancesxe2x80x94but at widths and spacing less than or greater than intended for the registration markings, and therefore having an overall length less than or greater than that of the encoderxe2x80x94and using the template to project an image onto a substrate at a suitable scaling factor to form the encoder having the correct widths and spacing of the registration markings on that substrate. The template may be a wholly computer-generated and memory-resident virtual image, or may be imprinted upon a tangible intermediate medium and transferred to the substrate using a projection technique. The scaling process may be accomplished using mechanical, optical, or photochemical techniques, as well as combinations thereof.
U.S. Pat. No. 4,722,297, entitled, Film Coater, relates to a coater that applies ultraviolet curable coating material to the opposite sides of roll film by a double-sided coater which employs offset coating rolls and smoothing bars. A splice detector responds to the occurrence of a splice upstream of the coater and causes the splice region to move through the coater without applying coating material to the splice region, by lifting the emulsion side of the film off of the coating roll as the splice passes and by temporarily and sequentially interrupting the operation of the smoothing bars and the offset applicator roller on the non-emulsion or base side, concurrently with the passage of the splice therepast. In a second embodiment, the film is lifted by lifting bars off of both coating rolls and tension on the film is concurrently decreased in the coater to prevent marking of the surface of the coated film by the final smoothing bars.
U.S. Pat. No. 4,612,875, entitled, Film Coater, relates to a coater that applies ultraviolet curable coating material to the opposite sides of roll film by a double-sided coater which employs offset coating rolls and smoothing bars. A splice detector responds to the occurrence of a splice upstream of the coater and causes the splice region to move through the coater without applying coating material to the splice region, by lifting the emulsion side of the film off of the coating roll as the splice passes and by interrupting the operation of the smoothing bars and the offset applicator roller on the non-emulsion or base side, concurrently with the passage of the splice therepast.
U.S. Pat. No. 4,447,468, entitled, Photographic Film Coating Apparatus And Method, relates to a spindled photographic film discs are coated with an ultraviolet light curable protective coating apparatus which receives a developer spindle carrying a plurality of film discs at a receiving station. Carry-in arms transfer the spindle into a coating station through a door and deposit the spindle at a location where the lower films on the stacked discs are partially submerged in a pool of coating liquid. A drive gear engages a spur gear on the spindle and slowly rotates the spindle for applying the coating evenly to the discs. Carry-over arms engage the spindle and carry it about the circumference of the drive gear, first lifting the spindle above the coating material and then causing the spindle to be spun at a relatively high rate for removing excess material from the discs. The carry-over arms thereafter transport the spindle through a second door and into an ultraviolet curing region while maintaining the rotation of the discs during curing. The carry-over arms thereafter deposit the spindle onto a carry-out conveyor where the spindle may be removed from the apparatus. The method includes the steps of partially lowering the film disc carried on a spindle to submerge the discs in a pool of coating material, elevating the spindle above the pool and rotating the same to spin off excess coating material, moving the spindle out of the coating region and into an ultraviolet light curing region while continuing the rotation of the spindle and the discs thereto to provide for even curing throughout the film areas of the spindle, and thereafter removing the spindle from the ultraviolet region.
U.S. Pat. No. 4,049,861, entitled, Abrasion Resistant Coatings, relates to abrasion resistant coatings comprising epoxy-terminated silanes cured in the presence of highly fluorinated aliphatic sulfonic and sulfonylic catalysts are solvent and abrasion resistant.
All documents cited herein, including the foregoing, are incorporated herein by reference in their entireties for all purposes.
The present invention is directed to encoder strips fabricated from a polymer sheet or film such as Mylarg(copyright) and a coating disposed on the encoder strip for dimensional stability and ink resistance. The markings on these polymer film encoder strips may be imprinted in a variety of ways, however the ultimate accuracy of the encoder strip is limited by the precision of the imprinting process or apparatus. High precision printing requires accuracy and an encoder strip must retain dimensional stability and remain substantially unclouded by ink residue for precision interaction with printing heads which rely on the markings. Resistance to ink clouding of the encoder strip is especially important in printing environments using agressive ink chemicals. In the past, ink clouded encoder strips have been routinely replaced at expense to the users.
The coatings advantageously limit damage and deformation of the encoder strip in a environmentally hostile environment due to factors such as humidity and ink residue. Deformation may result in contact between the print head and encoder strip which may damage one or both, or slow the print head due to friction. Subsequent stretching or distortion of the encoder strip would require periodic calibration. Clouding of the encoder by ink reside may cause printing, inaccuracies.
In sum, the invention relates to an encoder strip with dimensional stability and ink resistance properties including an element for use as an optical encoder strip. The element has a length, width, surface, thickness, and one or more markings per unit of length over at least a portion of the element. A coating has a thickness between about 2 microns and about 4 microns and is distributed substantially uniformly over the surface of the element. The coating is configured on the element as substantially translucent to one or more light wavelengths and is adapted to: (1) form a membrane to substantially prevent ink absorption into the element or adsorption to the surface of the element; and (2) provide dimensional stability to the element resulting from interaction of temperature and humidity. The coating may be about 3 microns thick. The coating and element may be configured such that: (1) the one or more markings as measured therebetween have a first dimension at a first time and a second dimension at a second time and the first and second dimension are substantially the same for maintaining a substantial precision in a resolution of the one or more markings; and (2) the one or more markings as measured have a first resolution at a first time and a second resolution at a second time and the first and second resolution are substantially the same for maintaining a substantial precision in a resolution of the one or more markings. The encoder strip may be adapted for use as a registration reference for the print head of a printer. The encoder strip may include Mylar(copyright). The markings may be generally parallel, spaced-apart opaque line segments alternating with generally transparent spaces. The encoder strip may be adapted for use on a wide-format printer or a wide-format plotter. The coating may substantially excludes moisture from absorbing into the encoder strip. The encoder strip may have a length of between about 40 inches and about 120 inches. The encoder strip may be used in an image reproduction system.
Still other objects and advantages of the present invention and methods of construction of the same will become readily apparent to those skilled in the art from the following detailed description, wherein only the preferred embodiments are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments and methods of construction, and its several details are capable of modification in various obvious respects, all without departing from the invention. Accordingly, the drawing and description are to be regarded as illustrative in nature, and not as restrictive.